The groundworker, who does not wish to be identified, was struck from behind by the vehicle as it delivered aggregates to a development on 7 August 2012.
He suffered serious injuries to his left leg, including a severed artery, a severely damaged thigh muscle and a large puncture wound. He was airlifted to hospital, and was unable to work for seven weeks.
Cheltenham Magistrates' Court heard on Friday (6 September) that his employer, Swindon-based John O'Flynn Developments Ltd, failed to put adequate safety measures in place to prevent the incident.
The firm was prosecuted by the Health & Safety Executive (HSE) after an investigation found that not enough was done to segregate workers on the ground from moving vehicles.
The injured working was using a noisy floor saw to cut a channel in a roadway when he was struck. The road should have been closed to site traffic, or vehicle movements closely supervised and monitored to ensure there was no risk.
John O'Flynn Developments Ltd, of Bramble Road, Swindon, was fined £10,000 and ordered to pay a further £3,892 in costs after pleading guilty to beaching Section 2(1) of the Health & Safety at Work etc Act 1974.
After the hearing, HSE inspector James Lucas said: "Despite the known risks of allowing vehicles unrestricted access on construction sites, numerous vehicles had to pass through the area where the injured worker and others were positioned in order to make deliveries.
"There were no measures were in place to safely segregate workers from vehicles, and as the worker had his back to the reversing vehicle as he used a noisy floor saw he did not see or hear it approach.
"John O'Flynn Developments failed to implement basic safety measures and an employee was seriously injured as a result."